Characters of Finite Quasigroups IV: Products and Superschemes

For finite loops (as for finite groups), the character table of a direct product is the tensor product of the character tables of the direct factors. This is no longer true for quasigroups. Although non-ℨ and ℨ-quasigroups may have the same character table, the character table of Q × Q determines whether a finite non-empty quasigroup Q lies in ℨ or not. A combinatorial interpretation of the tensor square of a quasigroup character table is obtained, in terms of superschemes, a higherdimensional extension of the concept of association scheme

Spectrum of TeV Particles in Warped Supersymmetric Grand Unification

In warped supersymmetric grand unification, XY gauge particles appear near the TeV scale along with Kaluza-Klein towers of the standard model gauge fields. In spite of this exotic low-energy physics, MSSM gauge coupling unification is preserved and proton decay is naturally suppressed. In this paper we study in detail the low-lying mass spectrum of superparticles and GUT particles in this theory, taking supersymmetry breaking to be localized to the TeV brane. The masses of the MSSM particles, Kaluza-Klein modes, and XY states are all determined by two parameters, one which fixes the strength of the supersymmetry breaking and the other which sets the scale of the infrared brane. A particularly interesting result is that for relatively strong supersymmetry breaking, the XY gauginos and the lowest Kaluza-Klein excitations of the MSSM gauginos may both lie within reach of the LHC, providing the possibility that the underlying unified gauge symmetry and the enhanced N=2 supersymmetry of the theory will both be revealed.Comment: 29 pages, 5 figure

Temperature effects on growth, colony development and carbon partitioning in three <i>Phaeocystis</i> species

Phaeocystis is an ecologically important marine phytoplankton genus that is globally distributed. We examined the effects of temperature on the 3 most common species: P. globosa, P. antarctica, and P. pouchetii, which grew at 16-32, 0-6, and 4-8 ° C, respectively. P. pouchetii did not form colonies; P. globosa formed colonies at 16, 20, and 24 ° C, and P. antarctica colonies were observed at all temperatures. More cells were partitioned into the colonial form at lower temperatures than at higher temperatures for P. globosa and P. antarctica. P. globosa colony size decreased with temperature, whereas P. antarctica colony size showed no distinct response to temperature. Numbers of cells per unit of colony surface area of P. globosa and P. antarctica were lowest at temperatures where highest growth rates and colonial abundances were observed; more organic carbon was partitioned into solitary cell biomass at higher temperatures, whereas the carbon concentration of colonies was not affected by temperature. Maximum quantum yield of P. antarctica and P. globosa exhibited subtle responses to temperature, whereas that of P. pouchetii was relatively invariant within the growth temperature range. Future changes in sea surface temperature may dramatically alter the ecology and biogeochemical cycles of systems dominated by Phaeocystis spp. and result in further degradation, via oxygen depletion and altered food web structure

Tidal influence on Rutford Ice Stream, West Antarctica: observations of surface flow and basal processes from closely-spaced GPS and passive seismic stations

High-resolution surface velocity measurements and passive seismic observations from Rutford Ice Stream, West Antarctica, 40 km upstream from the grounding line are presented. These measurements indicate a complex relationship between the ocean tides and currents, basal conditions and ice-stream flow. Both the mean basal seismicity and the velocity of the ice stream are modulated by the tides. Seismic activity increases twice during each semi-diurnal tidal cycle. The tidal analysis shows the largest velocity variation is at the fortnightly period, with smaller variations superimposed at diurnal and semi-diurnal frequencies. The general pattern of the observed velocity is two velocity peaks during each semi-diurnal tidal cycle, but sometimes three peaks are observed. This pattern of two or three peaks is more regular during spring tides, when the largest-amplitude velocity variations are observed, than during neap tides. This is the first time that velocity and level of seismicity are shown to correlate and respond to tidal forcing as far as 40 km upstream from the grounding line of a large ice stream

Evaluation of Several Algorithms in Forecasting Flood

Precise flood forecasting is desirable so as to have more lead time for taking appropriate prevention measures as well as evacuation actions. Although conceptual prediction models have apparent advantages in assisting physical understandings of the hydrological process, the spatial and temporal variability of characteristics of watershed and the number of variables involved in the modeling of the physical processes render them difficult to be manipulated other than by specialists. In this study, two hybrid models, namely, based on genetic algorithm-based artificial neural network and adaptive-network-based fuzzy inference system algorithms, are employed for flood forecasting in a channel reach of the Yangtze River. The new contributions made by this paper are the application of these two algorithms on flood forecasting problems in real prototype cases and the comparison of their performances with a benchmarking linear regression model in this field. It is found that these hybrid algorithms with a “black-box” approach are worthy tools since they not only explore a new solution approach but also demonstrate good accuracy performance.Department of Civil and Environmental EngineeringSeries: Lecture notes in computer scienceAuthor name used in this publication: K.W. Cha

Dynamics of vortex tangle without mutual friction in superfluid 4^4He

A recent experiment has shown that a tangle of quantized vortices in superfluid $^4$He decayed even at mK temperatures where the normal fluid was negligible and no mutual friction worked. Motivated by this experiment, this work studies numerically the dynamics of the vortex tangle without the mutual friction, thus showing that a self-similar cascade process, whereby large vortex loops break up to smaller ones, proceeds in the vortex tangle and is closely related with its free decay. This cascade process which may be covered with the mutual friction at higher temperatures is just the one at zero temperature Feynman proposed long ago. The full Biot-Savart calculation is made for dilute vortices, while the localized induction approximation is used for a dense tangle. The former finds the elementary scenario: the reconnection of the vortices excites vortex waves along them and makes them kinked, which could be suppressed if the mutual friction worked. The kinked parts reconnect with the vortex they belong to, dividing into small loops. The latter simulation under the localized induction approximation shows that such cascade process actually proceeds self-similarly in a dense tangle and continues to make small vortices. Considering that the vortices of the interatomic size no longer keep the picture of vortex, the cascade process leads to the decay of the vortex line density. The presence of the cascade process is supported also by investigating the classification of the reconnection type and the size distribution of vortices. The decay of the vortex line density is consistent with the solution of the Vinen's equation which was originally derived on the basis of the idea of homogeneous turbulence with the cascade process. The obtained result is compared with the recent Vinen's theory.Comment: 16 pages, 16 figures, submitted to PR

Breakdown of Particle-Hole Symmetry in the Lowest Landau Level Revealed by Tunneling Spectroscopy

Tunneling measurements on 2D electron gases at high magnetic field reveal a qualitative difference between the two spin sublevels of the lowest Landau level. While the tunneling current-voltage characteristic at filling factor $\nu = 1/2$ is a single peak shifted from zero bias by a Coulomb pseudogap, the spectrum at $\nu=3/2$ shows a well-resolved double peak structure. This difference is present regardless of whether $\nu =1/2$ and $\nu = 3/2$ occur at the same or different magnetic fields. No analogous effect is seen at $\nu = 5/2$ and 7/2 in the first excited Landau level.Comment: 5 pages, 4 figure

Low-Lying Excitations from the Yrast Line of Weakly Interacting Trapped Bosons

Through an extensive numerical study, we find that the low-lying, quasi-degenerate eigenenergies of weakly-interacting trapped N bosons with total angular momentum L are given in case of small L/N and sufficiently small L by E = L hbar omega + g[N(N-L/2-1)+1.59 n(n-1)/2], where omega is the frequency of the trapping potential and g is the strength of the repulsive contact interaction; the last term arises from the pairwise repulsive interaction among n octupole excitations and describes the lowest-lying excitation spectra from the Yrast line. In this case, the quadrupole modes do not interact with themselves and, together with the octupole modes, exhaust the low-lying spectra which are separated from others by N-linear energy gaps.Comment: 5 pages, RevTeX, 2 figures, revised version, submitted to PR

The significance of 'the visit' in an English category-B prison: Views from prisoners, prisoners' families and prison staff

A number of claims have been made regarding the importance of prisoners staying in touch with their family through prison visits, firstly from a humanitarian perspective of enabling family members to see each other, but also regarding the impact of maintaining family ties for successful rehabilitation, reintegration into society and reduced re-offending. This growing evidence base has resulted in increased support by the Prison Service for encouraging the family unit to remain intact during a prisoner’s incarceration. Despite its importance however, there has been a distinct lack of research examining the dynamics of families visiting relatives in prison. This paper explores perceptions of the same event – the visit – from the families’, prisoners’ and prison staffs' viewpoints in a category-B local prison in England. Qualitative data was collected with 30 prisoners’ families, 16 prisoners and 14 prison staff, as part of a broader evaluation of the visitors’ centre. The findings suggest that the three parties frame their perspective of visiting very differently. Prisoners’ families often see visits as an emotional minefield fraught with practical difficulties. Prisoners can view the visit as the highlight of their time in prison and often have many complaints about how visits are handled. Finally, prison staff see visits as potential security breaches and a major organisational operation. The paper addresses the current gap in our understanding of the prison visit and has implications for the Prison Service and wider social policy

Circumstellar interaction in supernovae in dense environments - an observational perspective

In a supernova explosion, the ejecta interacting with the surrounding circumstellar medium (CSM) give rise to variety of radiation. Since CSM is created from the mass lost from the progenitor star, it carries footprints of the late time evolution of the star. This is one of the unique ways to get a handle on the nature of the progenitor star system. Here, I will focus mainly on the supernovae (SNe) exploding in dense environments, a.k.a. Type IIn SNe. Radio and X-ray emission from this class of SNe have revealed important modifications in their radiation properties, due to the presence of high density CSM. Forward shock dominance of the X-ray emission, internal free-free absorption of the radio emission, episodic or non-steady mass loss rate, asymmetry in the explosion seem to be common properties of this class of SNe.Comment: Fixed minor typos. 31 pages, 9 figures, accepted for publication in Space Science Reviews. Chapter in International Space Science Institute (ISSI) Book on "Supernovae" to be published in Space Science Reviews by Springe